This invention relates to an apparatus for transporting paper signatures or the like to a processing line such as the collating conveyor of a binding machine. More specifically, the invention relates to apparatus for feeding signatures to the angularly spaced grippers of a rotary drum which, in turn, transfers the signatures to the collating conveyor of a so-called saddle stitch binding machine.
A rotary drum of the foregoing type is well known. The drum is rotated continuously and at high speeds and carries a pair of grippers adapted to rotate successively through a transfer station. At the transfer station, each open gripper receives the leading edge portion of a signature presented to the gripper and then closes upon the signature. With continued rotation of the drum, the gripper moves the signature toward the collating conveyor and then releases the signature for further handling by the conveyor.
Heretofore, apparatus for feeding a rotary drum of the foregoing type has consisted of a hopper for holding a queue of signatures on edge, along with conveyor means for feeding the signatures one-by-one and in spaced apart relation from the queue to the grippers of the drum. The conveyor means must be operated at a high speed in order to effect a high transfer rate. Operating the conveyor means at high speeds results in rapid wear and, in addition, extreme precision is required to insure that one signature, and one signature only, is pulled from the queue at a time and to insure that the signature is properly placed in the gripper.
In apparatus of the above type, the queue in the hopper is formed either by manually loading the signatures into the hopper or by automatically loading the hopper. In manually loaded systems, high skill and dexterity are required to establish and replenish a good queue which presents itself for handling in a precise fashion by the conveyor means. Moreover, one person is required to replenish the queues of several lines and thus is required to work with speed as well as accuracy. While automatically loaded systems are less labor intensive, presently available systems require considerable set up time and, in addition, the queues established by such systems are not as precise and reliable as those established by a skilled worker.